I'm betting he pitches a few games in Portland at the end of this year, starts next year in Portland, is called up to Pawtucket earlier in the year, then makes a spot start in Boston near the end of the year. This of course all assuming he keeps pitching well at each level. The Sox haven't really rushed a pitcher to the majors at all since Craig Hansen, and I think they learned their lesson on that one. My best guess is Barnes makes his MLB debut next August/September, and is in the starting rotation for good starting the beginning of the 2014 season at age 24.